A fossil is created when very specific circumstances occur. An animal fossil begins forming when an animal dies. The remains of the animal are buried in sediment, perhaps on a riverbank or in a lake. As the animal decomposes, the hard structures such as bone and horn are left behind. The sediment they are buried in is covered by more sediment and compressed. Eventually it becomes stone. Over time, the original animal parts are replaced by the different minerals in the stone.
Plant fossils are made differently. When part of a plant falls into sediment, it makes an impression. As the sediment hardens and the plant decomposes, minerals fill in the impression.
Most fossils are found when the stone they are buried in or imprinted on is eroded away by wind and water. They are found in riverbanks and beneath the water. In Florida, many are found in phosphate mines.
The Language of Fossils
There are many special words used in the identification of fossils. They include words like Miocene, Pleistocene, and Pliocene. These are the names of time periods in the distant past when different animals lived. The best known of these periods is the Jurassic, when many dinosaurs were alive. The time period we are in now is called the Holocene.
Besides words, abbreviations are also used in the study of fossils. One example of these abbreviations is “mya.” which means “million years ago”. Another is “bp” which means “before present”.
Fossils have scientific names just like plants and animals living today. The words in each name that are italicized are the genus and species. The genus is capitalized, and the species is not.
Many times, there are several species in the same genus. If this is the case, the genus name can be abbreviated to one letter. For example, the genus Equus has several species in it. Equus caballus is the domestic horse, E. quagga is the plains zebra, and E. grevyi is Grevy’s zebra.
There are also subspecies within species. For example, The Bengal tiger is Panthera tigris tigris and the Siberian tiger is P. tigris altaica.
To show how plants and animals are given scientific names, here is the name for the domesticated dog. Each division includes a description of what types of life forms fit into it. A scientist can tell a lot about a plant or animal if they know what it is named, even if they can’t see it.
Kingdom – Animalia (many celled, must eat to live, mobile for at least part of the life cycle)
Phylum – Chordata (has a notochord or spinal column)
Class – Mammalia (air breathing, nurse young, have hair/fur, have a complex brain structure called the neocortex)
Order – Carnivora (meat eater)
Family – Canidae (includes wolves and foxes)
Genus – Canis (wolves, coyotes, hyenas, jackals)
Species – C. lupus (wolves and dogs)
Subspecies – C. l. familiaris (domestic dogs)
Florida has changed many times in the millions of years that plants and animals have been here. It has been covered with water so deep that only a few pieces of land poked up as islands, and other times the coastline had been 300 miles further out than it is today. Many large animals lived in Florida in the past. These animals became extinct, but fossils of these bones and teeth are still there from which for us to learn from.
Inside the museum we have giant teeth that are from Columbian mammoths. Some of them are larger than a human head. They are made out of layers of hard tooth enamel and dentin, a type of cement. These materials wore down at different rates, so the teeth were always rough to break up the plants that mammoths ate.
We also have teeth of an ancient horse. These animals were plentiful in North America until 12,000 years ago. A combination of changing climate and human migration is believed to have caused their extinction. Many other large mammals became extinct around the same time, including the mammoth.
There are also fossils from ancestors of animals you can see in Florida today. The piece of jawbone in the case is from a baleen whale. Baleen whales, like the blue whale today, have curtains of hair instead of teeth. They use this hair to strain plankton, algae, and krill into their mouths. There is also a rib bone from an extinct dugong, which is the ancestor to the manatee.
Our collection includes turtle shell and plates from alligators. Reptiles living today look very much like their ancestors from long ago. They are often called ‘living fossils’ because they have not changed very much over millions of years.
Another animal that has not changed very much is the shark. Sharks have been around for 447 million years. Shark’s teeth are some of the most common fossils found in Florida. You can find them on the beach, in the ocean, and even in rivers.
Any vertebrate fossils found on state land belong to the state and cannot be removed. This includes all rivers and waterways. Fossil shark teeth are specifically excluded from these regulations, along with plants and invertebrate animals (mollusks, sea urchins, crabs, etc.). This means you do not need a permit to collect them.
You can obtain a permit to allow you to collect fossils on state lands. A child with a parent or guardian who has their own permit may collect fossils.
If you are collecting on private property, you need to have the owner’s permission. Even with a permit, you cannot collect on someone else’s property without their permission.
The local fossils that are on display at the museum were found along the Peace River Basin and in the Gulf of Mexico near Venice, Florida. They were donated by Bob “Flash” Cangiamila and Dian McKeithan – Miller.
Be sure and come to Port Boca Grande Lighthouse & Museum so that you can see all these wonderful fossils “up close and personal”. They’ve been waiting a long time for a visit!